Effects of insulin-like growth factor-1 on endoplasmic reticulum stress and autophagy in rat gastric smooth muscle cells cultured at different glucose concentrations in vitro. Mol Cell Biochem. 2019;451:11-20. [PMID: 30008033 DOI: 10.1007/s11010-018-3388-7]

Plant homeodomain-finger protein 5A: A key player in cancer progression

PHF5A is a member of the zinc-finger proteins. To advance knowledge on their role in carcinogenesis, data from experimental studies, animal models and clinical studies in different tumorigenesis have been reviewed. Furthermore, PHF5A as an oncogenic function, is frequently high expressed in tumor cells and a potential prognostic marker for different cancers. PHF5A is implicated in the regulation of cancer cell proliferation, invasion, migration and metastasis. Knockdown of PHF5A prevented the invasion and metastasis of tumor cells. Here, the role of PHF5A in different cancers and their possible mechanism in relation to recent literature is reviewed and discussed. There is an open promising perspective to their therapeutic management for different cancer types.

Insulin-like growth factor 1 in heat stress-induced neuroinflammation: novel perspective about the neuroprotective role of chromium

Heat stress (HS) can cause a series of stress responses, resulting in numerous negative effects on the body, such as the diminished food intake, carcass quality and reproductive capacity. In addition to the negative effects on the peripheral system, HS leads to central nervous system (CNS) disorders given its toll on neuroinflammation. This neuroinflammatory process is mainly mediated by microglia and astrocytes, which are involved in the activation of glial cells and the secretion of cytokines. While the regulation of inflammatory signaling has a close relationship with the expression of heat shock protein 70 (Hsp70), HS-induced neuroinflammation is closely related to the activation of the TLR4/NF-κB pathway. Moreover, oxidative stress and endoplasmic reticulum (ER) stress are key players in the development of neuroinflammation. Chromium (Cr) has been widely shown to have neuroprotective effects in both humans and animals, despite the lack of mechanistic evidence. Evidence has shown that Cr supplementation can increase the levels of insulin-like growth factor 1 (IGF-1), a major neurotrophic factor with anti-inflammatory and antioxidant effects. This review highlights recent advances in the attenuating effects and potential mechanisms of Cr-mediated IGF-1 actions on HS-induced neuroinflammation, providing presently existing evidence supporting the neuroprotective role of Cr.

Infantile hypertrophic pyloric stenosis: maternal diabetes and perinatal exposure to non-macrolide antibiotics

OBJECTIVE

Infant exposure to macrolide antibiotics is a risk factor for infantile hypertrophic pyloric stenosis (IHPS). The aim of the study was to establish whether perinatal exposure to non-macrolide antibiotics was a risk factor for IHPS.

STUDY DESIGN

A retrospective matched case-control study was performed using a database including all children born at Soroka University Medical Centre between 2006 and 2018. Cases and controls were compared using Student T-test and multiple logistic regression.

RESULT

Of 189 461 children in the database, 63 infants were diagnosed with IHPS and underwent pyloromyotomy. There was no association between non-macrolide antibiotic exposure and IHPS. Maternal diabetes (DM) had an adjusted odds ratio for infants developing IHPS of 4.53 (p = 0.004).

CONCLUSION

The lack of association between exposure to non-macrolide antibiotics and IHPS suggests a quality unique to macrolides. An association between DM and IHPS may suggest elevated levels of IGF-1 have a role.

Xiangsha Liujunzi Decoction improves gastrointestinal motility in functional dyspepsia with spleen deficiency syndrome by restoring mitochondrial quality control homeostasis

BACKGROUND

Xiang Sha Liu Junzi decoction (XSLJZD) is a famous traditional Chinese medicinal prescription for the treatment of functional dyspepsia (FD) in spleen deficiency. However, its therapeutic mechanism has not been fully clarified.

PURPOSE

The present study aimed to determine the role of mitochondrial quality control (MQC)-mediated gastrointestinal motility disorder in FD treated with XSLJZD by using spleen-deficient FD rats and gastrointestinal smooth muscle cells (GSMCs).

METHODS

In vivo, an FD with spleen deficiency syndrome model was established by gastric perfusion with iodoacetamide solution combined with the modified multiple platform method (MMPM), followed by intragastric gavage with XSLJZD for 4 weeks. Improvement of pathological symptoms was evaluated based on food intake, water intake, grip strength, gastric histopathological changes, gastric emptying rate, small intestinal propulsion rate, and average amplitude and frequency of smooth muscle strips. The mitochondrial ultrastructure was observed by transmission electron microscopy. The colocalization of LC3 and Parkin with mitochondria was detected by immunofluorescence. The expression and localization of Drp1 proteins were detected by immunohistochemistry. In vitro, GSMCs were treated with different concentrations of XSLJZD-CS for 24 h, followed by treatment with 20 μM carbon cyanide 3-chlorophenylhydrazone (CCCP) for 4 h. Cell viability, mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species (mtROS), cellular ATP generation and mitochondrial Keima (mtKeima) expression were examined. Both in vivo and in vitro, gene expression was assessed by Western blotting. All experiments were performed in duplicate.

RESULTS

Disorders of the mitochondrial quality control system existed in gastric smooth muscle in FD spleen deficiency syndrome. XSLJZD administration promoted the contraction of gastric smooth muscle and restored mitochondrial function by downregulating the colocalization of LC3 or Parkin with mitochondria, reducing the ratio of LC3II/LC3I, decreasing the expression of PINK1, Parkin and Drp1 and increasing the expression of p62 to restore mitochondrial morphology and function. In vitro studies showed that the improvement in mitochondrial function by XSLJZD was related to PINK1-parkin-mediated mitochondrial quality control.

CONCLUSION

We demonstrated that XSLJZD can improve gastrointestinal motility disorder in functional dyspepsia with spleen deficiency syndrome, which was related to reconstruction of the mitochondrial quality control system by restraining PINK1/Parkin-mediated mitophagy and division. This study illustrates a novel clinical significance of herbal medicine in the treatment of FD and clarifies the important role of MQC in treating gastrointestinal motility disorder.

Insulin-like growth factor-1 reduces hyperoxia-induced lung inflammation and oxidative stress and inhibits cell apoptosis through PERK/eIF2α/ATF4/CHOP signaling

Background: Insulin-like growth factor-1 (IGF-1), a member of the insulin family, has a high degree of homology with insulin and exhibits anti-inflammatory and anti-oxidative stress properties. However, the potential protective effect of IGF-1 on hyperoxia-induced lung injury remains unknown. In this study, we aimed to explore the effects and mechanism of action of IGF-1 in hyperoxia-induced lung injury in neonatal rats. Materials and Methods: Hematoxylin-eosin staining was used to observe pathological changes in lung tissue; transmission electron microscopy was used to examine the ultrastructure, and ELISA was used to detect the level of pro-inflammatory cytokines in bronchoalveolar lavage fluid. Further, malondialdehyde, glutathione, and superoxide dismutase activities in lung tissue were evaluated. TUNEL staining was used to detect cell apoptosis, and western blot analysis was used to detect the expression of Bax, Bcl-2, Caspase-3, p-PERK, p-eIF2α, ATF4, and CHOP in the lung tissue. Moreover, the wet/dry weight ratio of lung tissue was determined. Results: Intraperitoneal injection of IGF-1 effectively reduced lung tissue damage induced by hyperoxia; production of inflammatory cells and release of pro-inflammatory cytokines, oxidative stress, and cell apoptosis. Further, IGF-1 down-regulated the expression of ATF4, CHOP, and Bax/Bcl-2, and inhibited the phosphorylation of PERK and eIF2α. Conclusion: The results suggest that IGF-1 reduces hyperoxia-induced lung inflammation and oxidative stress in neonatal rats through the PERK/eIF2α/ATF4/CHOP signaling pathway and inhibits cell apoptosis.

Celecoxib attenuates hepatocyte apoptosis by inhibiting endoplasmic reticulum stress in thioacetamide-induced cirrhotic rats

BACKGROUND

Endoplasmic reticulum (ER) stress is an important mechanism in the progression of chronic and acute liver diseases, especially in the progression and recovery of liver fibrosis. Excessive and long-term ER stress induces apoptosis. ER stress-induced apoptosis is considered to be an important pathway in the development of liver fibrosis. Cyclooxygenase-2 (COX-2) induction is also closely related to ER stress. In our previous studies, we showed that celecoxib, a COX-2 inhibitor, improves liver fibrosis and portal hypertension. However, the role and mechanism of celecoxib in alleviating liver fibrosis remain unclear.

AIM

To investigate whether celecoxib alleviates liver fibrosis by inhibiting hepatocyte apoptosis via the ER stress response.

METHODS

Cirrhosis was induced by intraperitoneal injections of thioacetamide (TAA) for 16 wk (injection dose is 200 mg/kg per 3 d for the first 8 wk and 100 mg /kg per 3 d after 8 wk). Thirty-six male Sprague-Dawley rats were randomly divided into three groups, namely, control group, TAA group, and TAA + celecoxib group. In the last 8 wk, TAA-induced cirrhotic rats received celecoxib (20 mg/kg/day) or the vehicle by gastric gavage. After 16 wk, the rats were sacrificed, and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and albumin (ALB) were detected. The hepatic fibrosis areas were evaluated by Sirius red staining and the degree of fibrosis was assessed by measuring the level of hydroxyproline. ER stress levels were evaluated by detecting the marker proteins glucose-regulated protein 78 (GRP78), CCAAT/enhancer binding protein homologous protein (CHOP), PKR-like ER protein kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme 1 alpha (IRE1α). Apoptosis levels were evaluated by detecting caspase-12 and caspase-3.

RESULTS

The serum ALT and AST levels in the liver were significantly reduced by celecoxib; however, the serum ALB had no significant changes. Celecoxib significantly reduced the degree of liver fibrosis and the levels of hydroxyproline (-38% and -25.7%, respectively, P < 0.01). Celecoxib ameliorated ER stress by reducing the level of GRP78 compared to the TAA group (P < 0.05). Consistently, after celecoxib administration, the upregulation of TAA-induced hepatic apoptosis markers (caspase-12 and caspase-3) and CHOP were significantly inhibited. In addition, after celecoxib treatment, the expression of key molecules associated with ER stress (PERK, ATF6, and IRE1) was decreased (P < 0.05).

CONCLUSION

Therapeutic administration of celecoxib effectively reduces hepatic apoptosis in TAA-induced cirrhotic rats. The mechanism of action may be attributed to the suppression of CHOP expression, which subsequently inhibits ER stress.

Berberine attenuates mitochondrial dysfunction by inducing autophagic flux in myocardial hypoxia/reoxygenation injury

Berberine (BBR) is routinely prescribed in many Asian countries to treat diarrhea. Evidence from both animal and clinical investigations suggests that BBR exerts diverse pharmacological activities, including antidiabetic, antineoplastic, antihypertensive, and antiatherosclerotic effects. This study aimed to explore the cardioprotective mechanisms of BBR and to elucidate the modulations between autophagy and mitochondrial function during hypoxia/reoxygenation (H/R) in H9c2 cells. The degree of autophagic flux was assessed by pretreating H9c2 cells with BBR prior to H/R exposure and measuring the expression levels of Beclin-1 and green fluorescent protein (GFP)-labeled LC3B fusion proteins as well as the LC3II/LC3I ratio. The mitochondrial membrane potential (△Ψm) in H9c2 cells was evaluated by detecting rhodamine-123 fluorescence using flow cytometry. The results revealed that pretreatment with BBR upregulated autophagic flux and protected against the loss of the △Ψm in H9c2 cells subjected to H/R. We conclude that BBR attenuates mitochondrial dysfunction by inducing autophagic flux.

Effects of AMPK on Apoptosis and Energy Metabolism of Gastric Smooth Muscle Cells in Rats with Diabetic Gastroparesis

This study aimed to investigate the effect of AMPK on apoptosis and energy metabolism of gastric smooth muscle cells in diabetic rats and to explore the role of AMPK in the pathogenesis of diabetic gastroparesis (DGP). After establishment of a diabetic rat model, rats were divided into normal control (NC), 4-week (DM4W), 6-week (DM6W), and 8-week (DM8W) diabetic model groups. The gastric residual pigment ratio, intestinal transit rate, and intestinal propulsion rate in each group were detected to confirm the successful establishment of the DGP model. The spontaneous contraction in isolated gastric smooth muscle strips of the NC and DM8W groups was experimentally observed. The expression of phospho-AMPK, AMPK, phospho-LKB1, LKB1, phospho-TAK1, TAK1, and CaMMKβ in rat gastric smooth muscle tissues was detected by western blot analysis; ADP, AMP, ATP contents, and the energy charge were detected using Elisa; and apoptosis of gastric smooth muscle cells was detected by flow cytometry. The rat gastric smooth muscle cells were cultured in vitro, and treated with an AMPK inhibitor and an agonist. At 24 and 48 h, the effects of AMPK on apoptosis and energy metabolism of gastric smooth muscle cells were observed. Reduced spontaneous contractions, AMPK activation, cell apoptosis, and energy metabolism disorders were observed in gastric smooth muscle tissues of a diabetic rat, and AMPK activation was associated with an increased ratio of ADP/ATP, AMP/ATP, LKB1 activity, and CaMMKβ expression. From in vitro cell culture experiments, we found that AMPK activation of high-glucose conditions promoted cell apoptosis. Inhibition of AMPK had no obvious effect on apoptosis at the early stage with high glucose, but the inhibitory effect was significant at the late stage with high glucose. AMPK can regulate both mitochondrial metabolism and glycolysis pathways under high-glucose conditions. During the early stage with high glucose, AMPK was the main promotion factor of the mitochondrial metabolism pathway, but did not increase the ATP production, AMPK also promoted the glycolysis pathway. During the late stage with high glucose, AMPK was a major inhibitor of the mitochondrial pathway, and still played a role in promoting the glycolytic pathway, which acted as the main regulator. Apoptosis and energy metabolism disorders were present in gastric smooth muscle cells during the occurrence of DGP. Under high-glucose condition, AMPK was activated, which can promote apoptosis, change the energetic metabolism pathway of cells, inhibit mitochondrial energy metabolism, and promote glycolysis.

VEGF-A promotes angiogenesis after acute myocardial infarction through increasing ROS production and enhancing ER stress-mediated autophagy

Proangiogenesis is generally regarded as an effective approach for treating ischemic heart disease. Vascular endothelial growth factor (VEGF)-A is a strong and essential proangiogenic factor. Reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, and autophagy are implicated in the process of angiogenesis. This study is designed to clarify the regulatory mechanisms underlying VEGF-A, ROS, ER stress, autophagy, and angiogenesis in acute myocardial infarction (AMI). A mouse model of AMI was successfully established by occluding the left anterior descending coronary artery. Compared with the sham-operated mice, the microvessel density, VEGF-A content, ROS production, expression of vascular endothelial cadherin, positive expression of 78 kDa glucose-regulated protein/binding immunoglobulin protein (GRP78/Bip), and LC3 puncta in CD31-positive endothelial cells of the ischemic myocardium were overtly elevated. Moreover, VEGF-A exposure predominantly increased the expression of beclin-1, autophagy-related gene (ATG) 4, ATG5, inositol-requiring enzyme-1 (IRE-1), GRP78/Bip, and LC3-II/LC3-I as well as ROS production in the human umbilical vein endothelial cells (HUVECs) in a dose and time-dependent manner. Both beclin-1 small interfering RNA and 3-methyladenine treatment predominantly mitigated VEGF-A-induced tube formation and migration of HUVECs, but they failed to elicit any notable effect on VEGF-A-increased expression of GRP78/Bip. Tauroursodeoxycholic acid not only obviously abolished VEGF-A-induced increase of IRE-1, GRP78/Bip, beclin-1 expression, and LC3-II/LC3-I, but also negated VEGF-A-induced tube formation and migration of HUVECs. Furthermore, N-acetyl- l-cysteine markedly abrogated VEGF-A-increased ROS production, IRE-1, GRP78/Bip, beclin-1 expression, and LC3-II/LC3-I in the HUVECs. Taken together, our data demonstrated that increased spontaneous production of VEGF-A may induce angiogenesis after AMI through initiating ROS-ER stress-autophagy axis in the vascular endothelial cells.